gcc/gimple-streamer-in.c

   1 /* Routines for reading GIMPLE from a file stream.
   2
   3    Copyright (C) 2011-2015 Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@google.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "diagnostic.h"
  26 #include "alias.h"
  27 #include "backend.h"
  28 #include "tree.h"
  29 #include "gimple.h"
  30 #include "hard-reg-set.h"
  31 #include "ssa.h"
  32 #include "options.h"
  33 #include "fold-const.h"
  34 #include "internal-fn.h"
  35 #include "tree-eh.h"
  36 #include "gimple-iterator.h"
  37 #include "cgraph.h"
  38 #include "gimple-streamer.h"
  39 #include "value-prof.h"
  40
  41 /* Read a PHI function for basic block BB in function FN.  DATA_IN is
  42    the file being read.  IB is the input block to use for reading.  */
  43
  44 static gphi *
  45 input_phi (struct lto_input_block *ib, basic_block bb, struct data_in *data_in,
  46            struct function *fn)
  47 {
  48   unsigned HOST_WIDE_INT ix;
  49   tree phi_result;
  50   int i, len;
  51   gphi *result;
  52
  53   ix = streamer_read_uhwi (ib);
  54   phi_result = (*SSANAMES (fn))[ix];
  55   len = EDGE_COUNT (bb->preds);
  56   result = create_phi_node (phi_result, bb);
  57
  58   /* We have to go through a lookup process here because the preds in the
  59      reconstructed graph are generally in a different order than they
  60      were in the original program.  */
  61   for (i = 0; i < len; i++)
  62     {
  63       tree def = stream_read_tree (ib, data_in);
  64       int src_index = streamer_read_uhwi (ib);
  65       bitpack_d bp = streamer_read_bitpack (ib);
  66       /* Do not cache a location - we do not have API to get pointer to the
  67          location in PHI statement and we may trigger reallocation.  */
  68       location_t arg_loc = stream_input_location_now (&bp, data_in);
  69       basic_block sbb = BASIC_BLOCK_FOR_FN (fn, src_index);
  70
  71       edge e = NULL;
  72       int j;
  73
  74       for (j = 0; j < len; j++)
  75         if (EDGE_PRED (bb, j)->src == sbb)
  76           {
  77             e = EDGE_PRED (bb, j);
  78             break;
  79           }
  80
  81       add_phi_arg (result, def, e, arg_loc);
  82     }
  83
  84   return result;
  85 }
  86
  87
  88 /* Read a statement with tag TAG in function FN from block IB using
  89    descriptors in DATA_IN.  */
  90
  91 static gimple
  92 input_gimple_stmt (struct lto_input_block *ib, struct data_in *data_in,
  93                    enum LTO_tags tag)
  94 {
  95   gimple stmt;
  96   enum gimple_code code;
  97   unsigned HOST_WIDE_INT num_ops;
  98   size_t i;
  99   struct bitpack_d bp;
 100   bool has_hist;
 101
 102   code = lto_tag_to_gimple_code (tag);
 103
 104   /* Read the tuple header.  */
 105   bp = streamer_read_bitpack (ib);
 106   num_ops = bp_unpack_var_len_unsigned (&bp);
 107   stmt = gimple_alloc (code, num_ops);
 108   stmt->no_warning = bp_unpack_value (&bp, 1);
 109   if (is_gimple_assign (stmt))
 110     stmt->nontemporal_move = bp_unpack_value (&bp, 1);
 111   stmt->has_volatile_ops = bp_unpack_value (&bp, 1);
 112   has_hist = bp_unpack_value (&bp, 1);
 113   stmt->subcode = bp_unpack_var_len_unsigned (&bp);
 114
 115   /* Read location information.  Caching here makes no sense until streamer
 116      cache can handle the following gimple_set_block.  */
 117   gimple_set_location (stmt, stream_input_location_now (&bp, data_in));
 118
 119   /* Read lexical block reference.  */
 120   gimple_set_block (stmt, stream_read_tree (ib, data_in));
 121
 122   /* Read in all the operands.  */
 123   switch (code)
 124     {
 125     case GIMPLE_RESX:
 126       gimple_resx_set_region (as_a <gresx *> (stmt),
 127                               streamer_read_hwi (ib));
 128       break;
 129
 130     case GIMPLE_EH_MUST_NOT_THROW:
 131       gimple_eh_must_not_throw_set_fndecl (
 132         as_a <geh_mnt *> (stmt),
 133         stream_read_tree (ib, data_in));
 134       break;
 135
 136     case GIMPLE_EH_DISPATCH:
 137       gimple_eh_dispatch_set_region (as_a <geh_dispatch *> (stmt),
 138                                      streamer_read_hwi (ib));
 139       break;
 140
 141     case GIMPLE_ASM:
 142       {
 143         /* FIXME lto.  Move most of this into a new gimple_asm_set_string().  */
 144         gasm *asm_stmt = as_a <gasm *> (stmt);
 145         tree str;
 146         asm_stmt->ni = streamer_read_uhwi (ib);
 147         asm_stmt->no = streamer_read_uhwi (ib);
 148         asm_stmt->nc = streamer_read_uhwi (ib);
 149         asm_stmt->nl = streamer_read_uhwi (ib);
 150         str = streamer_read_string_cst (data_in, ib);
 151         asm_stmt->string = TREE_STRING_POINTER (str);
 152       }
 153       /* Fallthru  */
 154
 155     case GIMPLE_ASSIGN:
 156     case GIMPLE_CALL:
 157     case GIMPLE_RETURN:
 158     case GIMPLE_SWITCH:
 159     case GIMPLE_LABEL:
 160     case GIMPLE_COND:
 161     case GIMPLE_GOTO:
 162     case GIMPLE_DEBUG:
 163       for (i = 0; i < num_ops; i++)
 164         {
 165           tree *opp, op = stream_read_tree (ib, data_in);
 166           gimple_set_op (stmt, i, op);
 167           if (!op)
 168             continue;
 169
 170           opp = gimple_op_ptr (stmt, i);
 171           if (TREE_CODE (*opp) == ADDR_EXPR)
 172             opp = &TREE_OPERAND (*opp, 0);
 173           while (handled_component_p (*opp))
 174             opp = &TREE_OPERAND (*opp, 0);
 175           /* At LTO output time we wrap all global decls in MEM_REFs to
 176              allow seamless replacement with prevailing decls.  Undo this
 177              here if the prevailing decl allows for this.
 178              ???  Maybe we should simply fold all stmts.  */
 179           if (TREE_CODE (*opp) == MEM_REF
 180               && TREE_CODE (TREE_OPERAND (*opp, 0)) == ADDR_EXPR
 181               && integer_zerop (TREE_OPERAND (*opp, 1))
 182               && (TREE_THIS_VOLATILE (*opp)
 183                   == TREE_THIS_VOLATILE
 184                        (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0)))
 185               && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*opp, 1)))
 186               && (TREE_TYPE (*opp)
 187                   == TREE_TYPE (TREE_TYPE (TREE_OPERAND (*opp, 1))))
 188               && (TREE_TYPE (*opp)
 189                   == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0))))
 190             *opp = TREE_OPERAND (TREE_OPERAND (*opp, 0), 0);
 191         }
 192       if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 193         {
 194           if (gimple_call_internal_p (call_stmt))
 195             gimple_call_set_internal_fn
 196               (call_stmt, streamer_read_enum (ib, internal_fn, IFN_LAST));
 197           else
 198             gimple_call_set_fntype (call_stmt, stream_read_tree (ib, data_in));
 199         }
 200       break;
 201
 202     case GIMPLE_NOP:
 203     case GIMPLE_PREDICT:
 204       break;
 205
 206     case GIMPLE_TRANSACTION:
 207       gimple_transaction_set_label (as_a <gtransaction *> (stmt),
 208                                     stream_read_tree (ib, data_in));
 209       break;
 210
 211     default:
 212       internal_error ("bytecode stream: unknown GIMPLE statement tag %s",
 213                       lto_tag_name (tag));
 214     }
 215
 216   /* Update the properties of symbols, SSA names and labels associated
 217      with STMT.  */
 218   if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
 219     {
 220       tree lhs = gimple_get_lhs (stmt);
 221       if (lhs && TREE_CODE (lhs) == SSA_NAME)
 222         SSA_NAME_DEF_STMT (lhs) = stmt;
 223     }
 224   else if (code == GIMPLE_ASM)
 225     {
 226       gasm *asm_stmt = as_a <gasm *> (stmt);
 227       unsigned i;
 228
 229       for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
 230         {
 231           tree op = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
 232           if (TREE_CODE (op) == SSA_NAME)
 233             SSA_NAME_DEF_STMT (op) = stmt;
 234         }
 235     }
 236
 237   /* Reset alias information.  */
 238   if (code == GIMPLE_CALL)
 239     gimple_call_reset_alias_info (as_a <gcall *> (stmt));
 240
 241   /* Mark the statement modified so its operand vectors can be filled in.  */
 242   gimple_set_modified (stmt, true);
 243   if (has_hist)
 244     stream_in_histogram_value (ib, stmt);
 245
 246   return stmt;
 247 }
 248
 249
 250 /* Read a basic block with tag TAG from DATA_IN using input block IB.
 251    FN is the function being processed.  */
 252
 253 void
 254 input_bb (struct lto_input_block *ib, enum LTO_tags tag,
 255           struct data_in *data_in, struct function *fn,
 256           int count_materialization_scale)
 257 {
 258   unsigned int index;
 259   basic_block bb;
 260   gimple_stmt_iterator bsi;
 261
 262   /* This routine assumes that CFUN is set to FN, as it needs to call
 263      basic GIMPLE routines that use CFUN.  */
 264   gcc_assert (cfun == fn);
 265
 266   index = streamer_read_uhwi (ib);
 267   bb = BASIC_BLOCK_FOR_FN (fn, index);
 268
 269   bb->count = apply_scale (streamer_read_gcov_count (ib),
 270                            count_materialization_scale);
 271   bb->frequency = streamer_read_hwi (ib);
 272   bb->flags = streamer_read_hwi (ib);
 273
 274   /* LTO_bb1 has statements.  LTO_bb0 does not.  */
 275   if (tag == LTO_bb0)
 276     return;
 277
 278   bsi = gsi_start_bb (bb);
 279   tag = streamer_read_record_start (ib);
 280   while (tag)
 281     {
 282       gimple stmt = input_gimple_stmt (ib, data_in, tag);
 283       gsi_insert_after (&bsi, stmt, GSI_NEW_STMT);
 284
 285       /* After the statement, expect a 0 delimiter or the EH region
 286          that the previous statement belongs to.  */
 287       tag = streamer_read_record_start (ib);
 288       lto_tag_check_set (tag, 2, LTO_eh_region, LTO_null);
 289
 290       if (tag == LTO_eh_region)
 291         {
 292           HOST_WIDE_INT region = streamer_read_hwi (ib);
 293           gcc_assert (region == (int) region);
 294           add_stmt_to_eh_lp (stmt, region);
 295         }
 296
 297       tag = streamer_read_record_start (ib);
 298     }
 299
 300   tag = streamer_read_record_start (ib);
 301   while (tag)
 302     {
 303       input_phi (ib, bb, data_in, fn);
 304       tag = streamer_read_record_start (ib);
 305     }
 306 }